Hydraulic jack



J. A. KANUCH June 8, 1954 HYDRAULIC JACK 2 Sheets-Sheet l Filed May 10, 1950 @HIUHNN 1 m n NN. NN Wm.

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J- A. KANUCH HYDRAULIC JACK June 8, 1954 2 Sheets-Sheet 2 Filed May 1o, 195o muck Patented June 8, 1954 HYDRAULIC JACK John A. Kanuch, South Euclid, Ohio, assignor to Borg-Warner Corporation, Chicago, Ill., a corporation of Illinois Application May 10, 1950, Serial No. 161,087

(Cl. (S- 52) 7 Claims.

This invention relates to a hydraulic power unit, and more particularly to a manually operated hand pump incorporating a return valve operated by pivoting the pumping lever at right angles to its normal path of reciprocation.

In certain applications, it is sometimes desirable to employ a manually actuated hydraulic pump rather than a motor actuated pump. Thus, a manually operated hydraulic pump may be employed in conjunction with a light weight portable lift truck where it is not feasible or economical to provide a motor driven unit. In such applications, it is desirable to provide readily operable means for pumping vand then releasing the hydraulic pressure. Heretofore, a common practice has been to provide a manual valve which is turned by the operator to release pressure. Such manual valve is separate from the pumping unit, and its operation requires that the operator release the hand pumping lever in order to grasp the manual valve. For obvious reasons, this is undesirable.

An object of the present invention is to provide a new and improved hydraulic power unit, and more particularly a manually operated hydraulic power unit wherein operation of the pressure release valve is effected merely by pivoting the pumping lever substantially at right angles to its normal path of reciprocation.

A further object of the present invention is to provide a hydraulic power unit incorporating a relief valve in conjunction with the pressure release valve.

In accordance with one embodiment of this invention, a hydraulic power unit may be provided comprising a double acting piston type pump wherein the pump lever is reciprocated in one plane to cause pumping movement of the pistons and is moved at right angles to this plane to unseat a ball type release valve whereby hydraulic pressure in the system is released.

In accordance with a second embodiment of this invention, a relief valve may be provided for the hydraulic power unit control valve by employing a floating valve seat for the control or release valve, the valve seat being arranged to move to cause, in effect, opening of the control valve in response to the system pressure exceeding a predetermined desired maximum value.

Other objects and advantages of the present invention will be apparent from the following detailed description thereof taken in conjunction with the drawings, wherein:

Fig. 1 is a transverse, sectional view taken substantially along the line I-I of Fig. 2, and showing a double acting hydraulic power unit con- V2 structed in accordance with one embodiment of this invention; I

y 2 2 of Fig 1, and

Fig. 3 is a detail view of the return control valve of Fig. 2 showing this valve modied to serve also as a relief valve.`

The double acting hydraulic power unit shown in Figs. 1 and 2 is a substantially self-contained system designed to be sold as a package and comprises a housing I3 enclosingY an oil sump or reservoir I0 and a pair oi oppositely acting piston pumps II and I2. Operation of the piston pumps I I and I2 causes hydraulic fluid to be Withdrawn from the reservoir I0 and discharged through a common outlet port I formed in the mid portion of the housing I3, as viewed in Fig. 1. The clischarge port I4 may be connected by a suitable line I5 to a pressure responsive device such as a piston type hydraulic motor IB and return pressure from the plunger is communicated back to the power unit through the outlet port I4 to a return control valve I'I operated by the pump operator, as will be described.

As the piston pumps II and I2 are identical except for the left and right location thereof, respectively, as viewed in Fig. 1, the following detailed description of the pump assembly II applies equally to the pump assembly I2.

Piston pump assembly II is disposed in an elongated, kcylindrical chamber I8 formed in the left lower portion of housing I3 and extending transversely of Fig. l. A sleeve-shaped cylinder I9 is tted within the right portion of chamber I8, being retained therein by an inwardly extendingr shoulder 2i) of the chamber I8 against the left end of which the right side of a ange 2| integrally formed with the left end portion lof cylinder i9 bears. The nange 2l is provided with a peripheral, annular groove 22 to receive an O-ring seal,` whereby leakage of pressure between the wall of chamber I8 and periphery of cylinder I9 is avoided. Pump piston 23 is slidably journalled within cylinder I 9 and is provided with a passage 24 which extends axially through the piston from the left end thereof to a point slightly spaced from the right end thereof. Aperture 24 at its right end communicates with a radially extending aperture or port 25 whereby hydraulic fluid may be drawn into the piston chamber during the suction stroke. The location of the right end of the passage 2li must be such that at the end 0f the compression stroke of piston 23 the outer end of radial passage 25 is still in communication with the sump I0.

aesdse'? A check valve 26 comprising a ball poppet is arranged to seat on a valve seat 2'! provided by sharply enlarging the aperture 2li immediately adjacent its left end, the ball poppet being urged into seating relation by a small, very light spring 28, carried within the radially segmented or slotted left portion 30 of piston 23 and bearing at its left end against a dished expansion plug or plate 3I tted tightly within an annular, coaxially disposed recess 32 formed in the left, inner end of the segmented portion 30. Spring 28 exerts only sufficient pressure to move the ball valve 2G to closed position at the end of the suction stroke. During the suction stroke of piston 23, the ball poppet valve 26 readily opens permitting hydraulic iiuid to be drawn into the piston chamber; then, upon the piston reversing direction, the ball poppet 26 immediately seats and the fluid in the chamber is delivered under pressure.

Immediately adjacent the left end of sleeve cylinder i9 there is mounted an annular plate or disc 33 dening at its left, inner edge a valve seat 34 for a second ball poppet valve 35 mounted'on the left side of the plate 33 in axial alignment with the central aperture formed therethrough. The plate 33 bears at its right side against the left end of the sleeve cylinder I9. Like the flanged portion 2i of the sleeve cylinder, the plate 33 is provided with an annular peripheral groove 31 in which is positioned an O-ring seal 4B. The ball poppet valve 35 is urged into seating relation by a relatively heavy` coiled compression spring 4I, the left portion of which is received in a cylindrical recess 42 formed in a plug or closure block 43 mounted in the left side of housing i3, as viewed in Fig. 1. The closure plug i3 is. threaded into an enlarged left portion 434 of the piston chamber, and its right end bears against the left side of valve seat disc 33, thus holding the disc rigidly against the cylinder I9 and the cylinder I9 rigidly against the shoulder 23. It

` wiil be noted that the right end portion of retainer plug 43 is segmented or radially slotted, similarly to the left end of piston 23, the inner edges of the segmental portions 45 serving as guides for the poppet valve 35 to maintain the valve in correct axial alignment with valve seat 34, the poppet valve being loosely iitted between the segments.

During the suction stroke of the piston 23, the

ball poppet 35 is seated, preventing the pump piston from withdrawing r'luid from the outlet port I4. The ball poppet 35 also remains seated due to spring 4l when the pistons are not reciprocated. The ball poppet valve 35 is unseated only in response to the compression of the spring 4I being overcome by the pressure of the hydraulic fluid acting thereagainst in response to the pumping stroke of piston 23. Upon unseating of ball poppet 35, pressure duid is delivered to a sidewardly extending passage 46 which communicates with a vertically extending passage ll'i terminating at its lower end in outlet port I4. The passage 4B extends at an acute angle to the axis of reciprocation of piston 23, when viewed in plan view, so that one end thereof may communicate with the vertical passage 41 while the opposite end is in communication with pump chamber I8. A similar, angularly extending passage is, of course, provided for the right pump assembly I2, both passages connecting to the common outlet passage 47.

Reciprocation of the piston 23, and the corresponding, alternate reciprocation of the right pump assembly I2 is eected by pivoting a pump 4 lever arm 50 which is secured, at its lower end, to the right end of a hollow shaft 5i, as viewed in Fig. 2. Shaft 5I is journalled in housing I3 and has fixed thereto a cam block 52, the cam block 52 being provided with an aperture 53 through which the shaft 5i extends and a set screw 54 to lock the cam to the shaft. A downwardiy depending portion 55 of the cam provides a double faced cam surface, the curved, left side of downwardly depending portion 55 engaging the right end of piston 23, and the curved, right side of downwardly depending portion 55 engaging the left end of the corresponding piston of pump assembly I2.

More particularly, it will be noted that the opposed ends of the two pistons are provided with terminal portions of flattened and substantially reduced width. Termination 56 at the right end of piston 23 is connected to the correspondingly reduced termination of the right pump piston by a pair of links 51, the links 5l' being mounted on either side of each termination, in spaced relation, and the downwardly depending portion 55 of the cam 52 being disposed between the intermediate spaced portions. The links 5l' are made only suliiciently long so that the cam portion 55 may be iitted between the opposed ends of the pistons without substantial tolerance. At the same time the curved, piston end engaging, side surfaces of cam portion 55 are made to have a radius of curvature substantially equivalent to one-half the distance between the opposed piston ends. Thus, pivoting of the cam involves no change in the spacing between the pistons and a tight action is maintained.

From the foregoing, it will be evident that by pivoting or rocking the pump handle 55 back and forth in the plane of Fig. l, the pump pistons will be alternately reciprocated to cause delivery or" hydraulic pressure to the outlet port ill.

When it is desired to release pressure, that is, to permit return of pressure from the pressure actuated device through the outlet port I4, the return valve I'I is opened to provide a passage y to the sump I0. This is accomplished by pivoting the lever 50 to the left, as viewed in 2, that is to say, at right angles to its normal plane of movement, to cause a push rod 543 to move the ball valve 5I of the return valve assembly away from its seat. Ball valve SI is arranged to seat on a valve seat insert 52 of sleeve-shape which is mounted in a recessed portion `53 at the left end of a short passage 5t, formed in housing i3 and communicating at its right end with the sump chamber I0. The left end or tip portion of the push rod 63 is substantially smaller in diameter than the inner diameter of insert 52 and extends into insert S2 so that the left terminal end of the push rod may be engaged with the right side of ball valve 5I. By moving the push rod `50 to the left, the ball valve 6i may be unseated to permit return ilo-v of hydraulic uid.; when the bali valve 5I is unseated, a return passage is thus aiiorded from lthe common discharge passage 4l' to the Acontrol or return valve chamber 55, formed in housing i3, and from there to the sump through a short annular passage defined by the periphery of the reduced tip portion or" push rod 60 and the adjacent inner wall of insert G2 and passage 54.

The ball valve `IiI is normally urged to closed position by a coiled compression spring `65, the left portion of which is received in a relatively deep recess E1 formed in a retainer cap 58, which is in turn threaded into the left end of -chamber e5, as viewed in Fig. 2. It will be noted that the,

right end portion of the retainer cap 68 is reduced so that there is a substantial space between the periphery of the reduced portion 10 and the adjacent wall of chamber 65. The right end of cap -68 is spaced from the left end of insert 62 so that when the ball valve 6| is unseated, the fluid may pass to the sump. This terminal portion 'l also serves as a guide for the ball valve 6| which is loosely fitted therein. In some cases it may be desirable to axially slot the terminal portion 10 of the cap 68 to apply system pressure to the left side of ball valve -6| to aid in holding the valve seated.

The right portion of the push rod -60 is journalled in an axially extending aperture formed in the hollow shaft =5| and the right end of the push rod bears against the left end of an adjusting screw 12 threaded into and extending transversely of the pump lever 50. A coiled compression spring 13 surrounds'the right end portion of push rod `6|), being received in an enlarged or recessed portion I4 of ythe 'aperture 1| and the right end of the spring '|3 bearing against the left side of the lower end portion of lever arm `5|). The lower end of lever arm 50 is pivlotally supported vat a point substantially lower than the location of adj-usting screw '|2 on a transversely extending pivot or stub shaft 15, mounted at right angles to the axis of shaft 5|, the two ends of stub shaft 't5 being fixed in the opposed sides of a tubular member |6 in which member the lower portion of lever arm 50 is received. Member 1.6 is rigidly secured adjacent its lower mid portion to the right end of sleeve shaft 5l, as by welding; the left side of the portion of the arm 50 extending from the stub shaft 'I5 up to slightly bey-ond the upper end of tubular member 16 is cut away to provide a long recess or notch 1'| on the left side thereof, as viewed in Fig. 2. This permits lev-er arm 50 to be pivoted about the axis of shaft to the left, as viewed in Fig. 2, a suiiicient distance to cause the push rod 60 to unseat the ball valve 6|. This pivoting of arm 5D to unseat valve y6| may be done anywhere in the path of and during .the reciproycation of lever arm V5|] in the plane of Fig. 1.

In some cases it is desirable to incorporate a relief valve in the power unit. In accordance with the present invention, this may be done by employing a floating valve seat for the control valve, the valve seat being arranged to move in response to the system press-ure exceeding a predetermined maximum desired -value while the ball poppet is held or prevented from following the valve seat by the tip of push rod `6|).

Referring now to Fig. 3, showing a modification of the control valve l1 to provide a relief valve arrangement, it will be seen that a floating valve seat insert (i2-a is substituted for the valve seat insert 62 shown in Fig. 2 and Ithe insert 62-a .is slidably journalled in the right end of a slightly modified short passage {i3-a and is 'axially/ displaceable therein. The passage `63-Lt may comprise substantially only a slightly enlarged extension of valve -chamber `65. The left end of insert (i2-a abuts the right side of a shoulder 80 formed on the chamber wall at the point the passage ends and the chamber proper begins, the shoulder 80 preventing the sleeve insert from moving too far into the chamber. The right end of the sleeve insert `62h is reduced to define an annular ledge 81| against which the left end of a coiled compression spring 82, surrounding the tip of push rod y6|), bears, the vright end of spring 82 bearing against the left end of sleeve shaft 5|.

Preferably spring 82 is made su'iciently large inv -diameter to be located in coaxially spacedrelation to the push rod and the right end of spring 82 may be received in an annular recess 8-3 coaxially disposed `with respect to the axially extending aperture formed in shaft 5|.

When the system pressure exceeds a predetermined value, this pressure, exerted against the left side of poppet ball 6| and the left terminal end of valve seat [i2-a, will cause 'the floating valve seat 62-a to move to the right against the compression force exerted by spring 82. Poppet ball 6| is prevented from moving more than a very short distance to the right by engaging the left end or tipof push rod 60, but the valve seat (i2-a is free to move a sufficient distance away from the valve 6|, in accordance with the pressure exerted, to open the return passage defined by the periphery of the reduced left portion of push rod 60 and the relatively larger passage extending through insert (i2-a. During movement of floating valve seat SZ-a, axial alignment thereof with passage (i3-a and valve 6| is maintained because of the journal fit of the valve seat Vin the tip passage SS-a. Operation of the poppet Valve 6| as a return control valve is not affected by the provision of the floating valve seat since the valve seat remains substantially stationary until the relief pressure level has been exceeded. Ordinarily, this would be considerably higher than the normal operating pressure level. By

, properly selecting the compression value of spring 82, it will be evident that the opening or relief level may be established at any desired level.

Where herein the various parts of this invention have been referred to as being located in a right or a left position, it will be understood that this is done solely for the purpose of facilitating description and that such references relate only to the relative positions of the parts as shown in the accompanying drawings.

While but two embodiments of this invention have been shown and described, it will be understood that many changes and modifications may be made therein without departing from the spirit or scope of the invention. Also, While this invention has been described in conjunction with a double acting pump assembly, it will be evident that a single acting pump assembly may also be constructed within the scope of this invention.

What is claimed is:

1. In a hydraulic power unit including a low pressure uid reservoir, a pressure generator having at least two opposed oppositely acting piston type pumps in fluid vcommunication with said reservoir, manual means movable in one plane and pivotal about one axis effective to cause operation of said generator to deliver pressure fluid from said reservoir to a pressure actuated device and including camming means common to and serving to actuate said oppositely acting piston type pumps when said manual means is pivoted about the axis, said manual means being movable f in a second plane lying substantially at right angles to said first plane, and means in fluid communication with said pressure actuated device and said low pressure reservoir effective in response to movement of said manual means in said second plane to effect return iiow of uid from said device to said reservoir,`said last-mentioned means being disposed coaxially with said axis.

2. In a hydraulic power unit including a low pressure liquid reservoir, at least two opposed opdesde@ positely acting reciprocabie piston type liquid pressure generators in liquid communication with said reservoir adapted to deliver liquid from said reservoir to a pressure responsive motor, a pressure return iiow control valve assembly in liquid communication with said pressure responsive motor and with said reservoir, and a single, manually operable means having a rst pivotal movement about a rst axis effective to operate said pressure generators to cause the generation and delivery of pressure liquid from said reservoir to said pressure responsive motor and having a second planar movement eii'ective to operate said return flow control valve assembly for causing the return flow of liquid from said motor through said assembly to said reservoir, said return flow control valve assembly being disposed coaxially with said first-mentioned axis.

3. In a hydraulic power unit including a low pressure iluid reservoir, a pressure generator having a pair of opposed oppositeiy acting piston type pumps in communication with said reservoir, manual means movable through a first range of movement and pivotally connected to rotate about a first axis effective to cause operation of said generator to deliver pressure fluid from said reservoir to a fluid pressure actuated device and including a cam common to both piston type pumps, a combined release and relief valve associated with said pressure generator, said valve being in fluid communication with said motor and said reservoir, said valve including a plunger effective to cause said valve to operate alternately as a release or a relief valve and disposed for movement coaxially with the axis of rotation of said manual means, said manual means being movable through a second range effective to cause said plunger to move axially along the axis of rotation of said manual means to open said valve to permit return flow of fluid from said motor through said valve to said reservoir, said valve being arranged to open in response to return pressure exceeding a predetermined value to cause said iluid to return to said reservoir through said valve, the latter being effected by control of said plunger.

e. In a hydraulic power unit including a low pressure liquid reservoir, a pair of opposed oppositely acting reciprocable piston type liquid generators in liquid communication with said reservoir and adapted to deliver liquid to a pressure responsive device, a pressure return iiow control valve assembly in liquid communication with said 'pressure responsive device and with said reservoir, said valve assembly comprising a movable valve, seat, valve means cooperable with said seat, resilient means associated with said valve means for normally urging said valve means toward said seat, resilient means associated with said sea-t for normally urging said seat towards said Valve means, and manually operable means including camming means disposed between said oppositely acting pistons and common to both, said manually operable means being mounted for pivotal movement about a first axis and having a iirst movement effective to operate said pressure generators to cause delivery of pressure liquid from said reservoir to said pressure responsive device and having a second planar movement at substantially right angles to said nrst movement effective to unseat said valve means to cause pressure from said pressure responsive device to return to said reservoir through said valve assembly, said manually operable means further including a plunger mounted coaxially with said first-mentioned axis and in response to said second planar movement of said manual means, said valve seat being movable away from said valve means independently thereof in response to pressure from said pressure responsive device acting against said seat and exceeding a predetermined value to cause said pressure to return to said reservoir through said valve assembly, the latter being accomplished by said axially disposed plunger.

5. In a hydraulic power unit, a. low pressure liquid reservoir, a reciprocable piston type pressure generator in liquid communication with said reservoir and adapted to deliver liquid to a pressure responsive device, means for actuating said generator, said means including a manually operable means mounted for rotation about a iirst axis, a valve assembly in liquid communication with said reservoir and located on the discharge side of said generator, said valve assembly being disposed coaxially with the axis of said manually operable means and including means deiining a valve chamber, an annular iioating valve seat journalled in said chamber, stop means for limiting movement of said valve seat in one direction, resilient means for urging said valve seat towards said stop means, and a valve arranged to seat on said valve seat when said valve sea-t is positioned against said stop means, and means associated with 'said pressure generator actuating means and mounted coaxially with said inst-mentioned axis for moving said valve off said valve seat to cause pressure from the discharge side of said generator to return to said reservoir through said valve assembly.

6. A hydraulic power unit in accordance with claim 5 wherein said pressure generator actuating means comprises manual means movable in one plane effective to cause operation of said generators to deliver pressure liquid to said pressure responsvedevice, said manually actuated means being movable in a second plane lying substantially at right angles to said rst plane to effect return flow of liquid from said device by unseating said valve from said movable valve seat.

7. In a pressure generator comprising a low pressure reservoir, a pair of pump cylinders, pistons in said cylinders, said cylinders and pistons being arranged to deiine oppositely acting pumps in communication With said reservoir, a camming means, a shaft, said ca-mming means being disposed on said shaft intermediate said oppositeiy acting pistons; a hand lever connected to said shaft for actuating the same thus effective to operate said pistons, said hand lever being pivotally movable in one direction to accomplish generation of pressure by said piston pumps, a return ilow control valve assembly in communication with the discharge side of said pumps on one side and with the low pressure reservoir on the other side, said valve assembly being mounted coaxially with said shaft and comprising a movable valve seat, valve means cooperable with said seat, resilient means associated with said valve means for normally urging said valve means towards said seat, resilient means associated with said seat for normally urging said seat towards said valve means, a plunger mounted coaxially with said shaft and reciprccable therethrough, said plunger effective to cause said valve means to move away from said seat to cause pressure generated by said pumps to return to said reservoir through said valve assembly, said movement being accomplished either by movement of said plunger through movement of said hand lever in a second pivotal direction -or by movement of said movable References Cited in the le of this patent UNITED STATES PATENTS Number Name Date Hamilton July 17, 1866 Lewis Mar. 12, 1878 Caldwell O'ct. 13, 1896 Jakob Nov. 5, 1929 Brown Oct. 20, 1936 Number Number Name Date Lowe Mar. 1-6, 1937 Pomeroy June 22, 1943 Richards May 20, 1947 Roth May 17, 1949 Noble May 31, 1949 Schneck May 31, 1949 Hardy July 11, 1950 FOREIGN PATENTS Country Date Germany June 1, 1934 Great Britain June 11, 1931 

